Not to be confused with extensions, plug-ins generally have a focused set of abilities that enables customization of an application and WordPress has made extensive use of plug-ins since it was introduced in 2003.

The first plug-in appeared in the 1970s – the EDT text editor on the Unisys VS/9 operating system for the Univac 90/60 series mainframe computer – and were incorporated into even early PC software such as Apple’s HyperCard and Quark, Inc’s., QuarkXPress on the Macintosh in 1987, and Silicon Beach Software’s Digital Darkroom and SuperPaint in 1988.

Well-known plug-ins in use today include Adobe Flash Player and Apple’s QuickTime, with Mozilla Firefox also making extensive use of plug-ins to display video, play audio and render animations.

Plug-ins are basically stand-alone pieces of code that can execute actions in different parts and stages of a webpage or an entire website, and provide an easy method of tailoring a website to deliver enhanced user experiences and to deliver increased functionality.

Today there are thousands of free and premium WordPress plug-ins available to improve functionality and features for WordPress-based websites and the following are the WordPress plug-ins that we find ourselves returning to over and over again:

Our most often used and useful WordPress plug-ins

WordPress is similar to the Zarya control module of the ISS - powerful, compact, and fully able to function by itself. Photo: Courtesy NASA